Ultrafast UV photon echo peak shift and fluorescence up conversion studies of non-polar solvation dynamics

Oskouei, Ahmad Ajdarzadeh; Bräm, Olivier; Cannizzo, Andrea; Mourik, Frank van; Tortschanoff, A.; Chergui, Majed

doi:10.1016/j.chemphys.2008.01.029

Cited by 33 publications

(31 citation statements)

References 54 publications

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“…For MTHF Ã , the emission spectrum (Fig. 2) clearly shows certain features, similar to a vibronic structure often observed for dye molecules in nonpolar or rigid environments (35). For FADH −Ã , the emission spectra (Fig.…”

Section: Resultsmentioning

confidence: 84%

Ultrafast solvation dynamics at binding and active sites of photolyases

Chang

Guo

Kao

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Dynamic solvation at binding and active sites is critical to protein recognition and enzyme catalysis. We report here the complete characterization of ultrafast solvation dynamics at the recognition site of photoantenna molecule and at the active site of cofactor/ substrate in enzyme photolyase by examining femtosecondresolved fluorescence dynamics and the entire emission spectra. With direct use of intrinsic antenna and cofactor chromophores, we observed the local environment relaxation on the time scales from a few picoseconds to nearly a nanosecond. Unlike conventional solvation where the Stokes shift is apparent, we observed obvious spectral shape changes with the minor, small, and large spectral shifts in three function sites. These emission profile changes directly reflect the modulation of chromophore's excited states by locally constrained protein and trapped-water collective motions. Such heterogeneous dynamics continuously tune local configurations to optimize photolyase's function through resonance energy transfer from the antenna to the cofactor for energy efficiency and then electron transfer between the cofactor and the substrate for repair of damaged DNA. Such unusual solvation and synergetic dynamics should be general in function sites of proteins.function-site solvation | ultrafast dynamics | spectral tuning | protein rigidity and flexibility | femtosecond-resolved emission spectra D ynamic solvation in binding and active sites plays a critical role in protein recognition and enzyme reaction, and such local motions optimize spatial configurations and minimize energetic pathways (1-11). These dynamics involve local constrained protein and trapped-water motions within angstrom distance and occur on ultrafast time scales (6,7,10,11). Typically, extrinsic dye molecules or synthetic amino acids were used as local optical probes to label function sites, and the local relaxations were observed, ranging from femtoseconds to nanoseconds (5,(12)(13)(14). Such labeling of bulky dye molecules usually induces significant local perturbations, and direct characterization with intrinsic chromophores in proteins eliminates those interferences and reveals intact environment responses (4, 7, 15-21), as recently examined in green fluorescence proteins (21). We have recently studied a series of flavoproteins using intrinsic flavin molecule as the optical probe (10, 22, 23) and especially found the important functional role of local solvation in photolyase (10).Photolyase, a flavoprotein and a photoenzyme, repairs damaged DNA caused by UV irradiation. Two types of structurally similar photolyases are specific for two major UV-induced DNA lesions of cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct (24). The CPD photolyase contains two noncovalently bound chromophores, a pterin molecule in the form of methenyltetrahydrofolate (MTHF) in the binding site as the photoantenna for energy efficiency and a fully reduced flavin adenine dinucleotide (FADH − ) at the active site as the catalytic cofactor for repair of d...

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Section: Resultsmentioning

confidence: 84%

Ultrafast solvation dynamics at binding and active sites of photolyases

Chang

Guo

Kao

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…These difficulties have prevented photon echo ͑PE͒ experiments from being implemented in the UV range, and only the work of Fayer and co-workers 19 existed prior to our studies. 20,21 They investigated the dephasing time of the diphenylacetylene ͑DPA͒ in cyclohexane with a two-pulse photon echo technique, and estimated it to be 500 fs using a pulse length dependent theoretical method. Despite a good temporal resolution ͓full width at half maximum ͑FWHM͒ Ϸ 80 fs͔, they could not measure the dephasing time directly because of the presence of the nonresonant signal from the solvent.…”

Section: Introductionmentioning

confidence: 99%

Three pulse UV photon echo studies of molecules in solution: Effect of the chirp

Oskouei

Tortschanoff

Bräm

et al. 2010

The Journal of Chemical Physics

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We report on the electronic dephasing times of the nonpolar chromophore diphenylacetylene (DPA) in ethanol and in cyclohexane (polar and nonpolar solvents respectively) by photon echo measurements in the ultraviolet. Contrary to previous reports, we observed sub-100-fs electronic dephasing times for DPA in both solvents. We identify fast dynamics of tau=40+/-10 fs on the photon echo peak shift (PEPS) traces of DPA in ethanol. In addition, we observed a dependence of the PEPS asymptotic value on the temporal chirp of the pulses. We propose a model to describe it in terms of phase-matching condition and beam geometry.

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“…In 'photon echo' methods, the time coherence properties of the excited states, which can include electronic wavefunctions arising from low-energy electronic excitations in complex molecular systems, are determined by monitoring the variation of the FWM signal as a function of the relative delay between the two excitation pulses [32]. So far, the shortest wavelength where these techniques were applied is the UV just below 300 nm [33][34][35]. Pushing their limits to shorter wavelengths allows accessing the core levels, with the advantage of elemental specificity.…”

Section: Vacuum Ultraviolet/soft X-ray Four Wave Mixing: An Atomic Sementioning

confidence: 99%

Nanoscale dynamics by short-wavelength four wave mixing experiments

et al. 2013

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Multi-dimensional spectroscopies with vacuum ultraviolet (VUV)/x-ray free-electron laser (FEL) sources would open up unique capabilities for dynamic studies of matter at the femtosecond-nanometer time-length scales. Using sequences of ultrafast VUV/x-ray pulses tuned to electron transitions enables element-specific studies of charge and energy flow between constituent atoms, which embody the very essence of chemistry and condensed matter physics. A remarkable step forward towards this goal would be achieved by extending the four wave mixing (FWM) approach at VUV/soft x-ray wavelengths, thanks to the use of fully coherent sources, such as seeded FELs. Here, we demonstrate the feasibility of VUV/soft x-ray 7

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Ultrafast UV photon echo peak shift and fluorescence up conversion studies of non-polar solvation dynamics

Cited by 33 publications

References 54 publications

Ultrafast solvation dynamics at binding and active sites of photolyases

Ultrafast solvation dynamics at binding and active sites of photolyases

Three pulse UV photon echo studies of molecules in solution: Effect of the chirp

Nanoscale dynamics by short-wavelength four wave mixing experiments

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